Time division multiplexed (TDM) data streams (including voice, data, and private lease line services) have very strict timing and frequency requirements. As a result, traditionally, TDM data streams have been transported in TDM circuits to ensure a continuous transport of bit streams to meet such timing and frequency requirements. For example, a T1 line leased to transport TDM digital signals may be divided into 24 channels. Each channel connects two physical locations (e.g., point A and point B).
Recently, many existing systems have attempted to use networks, such as asynchronous transfer mode (ATM) networks, to emulate TDM circuits to perform more efficient transfers of TDM data streams. These networks have to emulate TDM circuits in order to meet the strict TDM timing and frequency requirements.
To date, however, there is no effective method to transport TDM data streams over a packet network, such as the MPLS network. Using packet networks is desirable because packet networks are currently the fastest growing of all transport means. One problem to overcome before achieving an efficient use of packet technology is to cope with or reduce the possibility of violating the strict TDM technology timing and frequency requirements. Another problem to overcome is to cope with or reduce the probability of dropped or scrambled packets in a data stream.
Thus, it is desirable to provide apparatus and methods that provide circuit emulation of a point-to-point protocol operating over a MPLS network to process TDM data streams.